Background: Glaucoma is the leading cause of global irreversible blindness optic neuropathy and retinal ganglion cell (RGC) death are the hallmarks of glaucoma. If intraocular pressure (IOP) is held within “normal" ranges, the disease process and RGC death can still progress in some patients. Neuroprotective therapies for glaucoma should aim to halt RGC loss thus preventing further structural and functional damage of the optic nerve Objective: The aim of the current work was to study the ability of visual field testing and optical coherence tomography to reveal the neuroprotective role of brimonidine. Patients and Methods: This prospective randomized controlled trial study included a total of 98 eyes from 50 patients affected by primary open-angle glaucoma (POAG). They were recruited from a larger population of 70 POAG patients, attending at Menofiya University Hospitals. Results: The use of visual field-testing parameters have revealed that brimonidine had insignificantly halted glaucoma progression: MD (-0.1115 dB and -.2465 dB), VFI (-0.5882 and-1.1471) and PSD (0.1729 and 0.1894). On the other hand, some OCT parameters: average RNFL thickness (-0.7273 u and-2.2121 u), inferior RNFL thickness (-0.735 u and -1.559 u), superior RNFL thickness (-0.6364u and -1.4848 u), rim area (-0.0162 mm² and-0.0797 mm²), average cup disc ratio (-0.01765 and 0.01824) and vertical cup disc ratio (-0.0167 and 0.0321) for study and control groups respectively, gave promising neuroprotective results for brimonidine. Conclusion: It could be concluded that the use of visual field-testing parameters (MD, VFI and PSD) has revealed that brimonidine had insignificantly halted glaucoma progression.